Telephone-receiver



(No Model.)

W. C. TURNBULL.

TELEPHONE RECEIVER.

No..346,962. Patented Aug. l0, 1886.

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VILLIAM C. TUBJNBULIt AOF BALTIMORE, MARYLAND.

TELEPHONE-RECEIVER.

SPECIFICATION forming part of Letters Patent No. 346,962, dated August10, 1886.

Application filed February 23,1886. Serial No. 192,916. (hjo model.)

To all whom t may concern,.-

Bc it known that I, WILLIAM C. TURNBULL', of Baltimore, in the State ofMaryland, have invented certain new and useful Improvements inTelephone-Receivers, of which the following is a specification.

The object of my invention is to improve the construction and operationof telephonie receivers; and to this end the invention primarilyconsistsin employing a vibrating plate, preferably rectangular, andsustained at two opposite edges only, preferably under tension.

In the accompanying drawings,Figure lis a longitudinal section throughone form of apparatus; Fig. 2, a similar section through an otherslightly modified form of apparatus; Fig. 3, a detail view of thevibrating-platesupport, showing the edges of the vibrating plate insection. Fig. 4 is an end View ofthe same. Fig. 5 is a view similar toFig. 3, showing the form of support employed in the instrument shown inFig.` 2, Fig. 6, an under end view of the same, and Fig. 7 is aperspective detail view of my improved dat tubular receiving vibrator.

I preferably carry out my invention by employing a fiat tube ofinductive metal,substan tially such as that shown in Fig. 7. The widthof this tube relatively to its thickness and length is practicallyimmaterial, though I prefer to makethe width about equal to the lengthand the thickness about as illustratedv in the drawings,which show apractical full-size operative structure. rIhe flat tubeA may beheld inany suitable way; but I prefer to employ such an arrangement as thatshown in Figs. 3 and 5, which show a support, B, of approximately thesame cross-section as the flat tube A, and depressed or cut away on itsopposite flat faces, so as to leave depressions or vocalizing-cbambers bopposite the flat sides a of the tube A when the latter is in place onits support, as indicated in the drawings. It will be observed that bythis structure each side of the flat tube -A becomes a plate capable ofvibrating in response to the action of a re ceiving electromagnet, and Imay employ one or both sides, as may be desired.

In the drawings I Yhave shown magnets operating upon both sides of theflat tube, and I prefer so to make the instrument.

In order to maintain the flat tube under tension, the support B is madeof such a size as to tightly stretch the flat sides. of thc tube A whenthe tube is forced over the support. The support B is cut away, asshown, at its upper edge on each side, so as to formpassages on eachside of a dividing-ridge, c, to the vocalizing-chambers b b.

In the form of instrument shown in Fig. 1, the support B, which ispreferably of wood, hard rubber, or vulcanized fiber, is shown as formedwith a prolongation which is clamped between the legs of two fiatbar-magnets, which are bent outwardly at their upper ends, soas toafford spaces opposite the vibrating plates for the reception ofsuitable coils and cores, C. The instrument is inclosed in any suitablecase.

In Fig. 2 I have shown asingle bar-magnet, upon the upper end of which,as viewed in the drawings, is mounted a soft-iron pole-piecc, D, havingtwo upright arms which terminate opposite the inductive vibratingplates, and carry core-pieces upon which ordinary coils are arranged.The support B may be secured to the piece D in any suitable way.

The structure which has now been briefly described is practical and veryeflicient. Obviously, however, the invention does not depend, so far-asthe use of a vibrating plate secured at two edges only is concerned,upon the employment of a 'flat tubeg'and, as before remarked, one plateonly may be employed instead of a dat tube; or, where a flat tube isused, only one side may be utilized. The vocalizing chambers ordepressions formed in the sides ofthe support B, might of course beturned out so as'to be circular instead of rectangular, as illustrated.

I am aware of the patent of Thompson, No. 339,500, of April 6, 1886,which showsa plate of non-magnetic material located out of the magneticfield of the telephone-magnet and confined at two opposite ends. I amalso aware of the patent ofEickcmeyer,No. 210,929, of December 17, 1878.I do not therefore claim any subject-matter shown in either-of thesecases, the features of my invention being specifically claimed below.

I claim as my invention- 1. The combination of the magnet and a Vi- IOObrating rectangular receiving-plate of inductive metal arranged in thefield of the magnet, supported at two opposite edges, and free tovibrate between said supports, substantially as and for the purpose setforth.

2. In a telephone-receiver, the combination of a receiving-magnet andarectangular receiving-plate of inductive metal arranged in the iield ofsaid magnet, supported at two opposite edges only under tension, andbeing free to vibrate between said supports.

3. The combination of the dat tube of inductive metal and its supportformed with the recesses or voalizing-chambers b.

4. The combination of the fiat tube of inductive metal and its supportformed with suitable vocaliziug-chambers, and ont away,

